Link insulator



July 8 1924. 1,500,814

E. M. HEWLETT LINK INSULATOR Filed Sent. 14. 1921 Inventor Edward M. Hewlett,

His Attorney Patented July 8, 192a UNITED STATES PATENT OFFICE.

EDWARD I. HEWLETT, OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

LIN K INSULA'IOR.

- Application am September 14, 1921. Serial ms. 500,490.

To all whom it may concern:

Be it known that I, EDWARD M. HEWLE'I'I, a citizen of the United States, residing at Schenectady, State of New York, have invented certain new and useful Improvements in Link Insulators, of which the following is a specification.

The resent invention relates to insulators for hig potential electric power transmission lines and more especially to strain or dead-end insulators for supporting and anchoring such line wires subjected to excessive longitudinal stresses.

Since the introduction of the suspension system of the Buck and Hewlett Patent 925,561, the working potentials of transmission circuits have m many instances been qluadrupled and the distances over which e ectric power is transmitted have been correspondmgly increased and at the present time the insulator problem is no longer the limitin factor in electric power transmission. owever, the greater potentials and longer distances of transmission have made necessary greater and stronger insulator units especially for sustaining extra high potentials and extra long spans as at crossings of rivers and deep ravines for example.

The object of my invention is to provlde an improved form of insulator unit for use in sus ension systems of electric power transmission which shall be capable of resisting much higher mechanical and electrical stresses than the insulator units heretofore in use on such systems.

One embodiment of my invention is shown in the accompanying draw' g in which Fig. 1 is a perspective viewo the insulator unit and the .metal connectors; Fig. 2 is a transversecentral section, and Fig. 3 is a longitudinal axial section thereof.

The insulator consists of a single iece of porcelain or other insulating material having interlinked passageways 1 and 2 disposed therein in planes at right angles to each other for the reception of metallic links 3 of U-shape whereby the stresses imposed on the insu ator by the two links pulling in opposite directions will be compressive only and practically confined to the central or body portion 4 of the insulator. The body portion 4 is accordingly made so as to provide a substantial t 'ckness of insulating material between the passageways 1 and 2,

in. the county of Schenectady,

and in order to avoid concentration of the pressure exerted by the metallic links 3, the bearing surfaces are made cylindrical.

In order that the link carried in passageway 1 may be shut in electrically, a barrier wal 5 (see Fig. 1) extends in a U-shape thereabout with the'body portion l forming a transverse bridge centrally between the parallel portions of the wall while the outer ends of the U-shaped wall 5 are continued into oppositely disposed semi-circular end flanges 6 lying in the same transverse plane and constituting a head. The link in passageway 2 is electrically shut in by two wide cross walls 7 extending transversely to the U- shaped wall 5 and joining at their rear edges with the said semi-circular end flanges 6 and centrally with the body portion 4. The U-shaped wall 5 and the cross walls 7 are disposed somewhat divergently so as to afford approach room to the passageways 1 and 2 and also to facilitate manufacture.

The cross walls 7 are made wide enough to extend at their outer edges beyond the crown of the U-shaped wall 5 and thereby form continuous overhangs or eaves 8 at their forward edges.

The metallic U-shaped links 3 are made from round bars flattened throughout the bent portions 9 to provide enlar ed bearing contact with the cylindrical sur aces of the passageways through the insulator and their ends are upset to form heads 10 to afford grips for the split clamps 11 which are held together by bolts 12.

-lVhen installed a number of insulator units will be connected in series, upon the potential of the power current, and their axis'will align with the catenary of the wire span and the axis of eachinsulator will ordinaril be at an acute angle to the horizontal. l sulator with its headed end the i her, an water fallin upon the unit wi run 0 from the si e upon which it falls without tending to join withthe water flowin off the opposite side. Assuming the osition of the insulator shown in Fig. 1 to typidepending installing each m-. I

cal, the water falling upon the. left-hand By reason of the rain-shedding qualities and the very large creepage surface of my insulator, its resistivity to the escape of electric current thereover is rendered much greater than that of any insulator of corresponding diameter heretofore in use and as a consequence a less number in series will be required for a given otential. On account of the symmetrical distribution of material in my insulator, there is a slight danger of the insulator being injuriously affected by shrinkage strains.

While I have described and shown the best form of embodiment of the invention known to me, I do not desire to be restricted thereto.

What I claim as new'and desire to secure by Letters Patent of the United States, is

1. An insulator unit having a central or body portion provided with two interlinked passageways, a barrier wall extending in U-- shape about one of said passageways, semicircular flanges extending radially from the ends of said barrier wall, and two substantially parallel barrier walls disposed transversely of said U-shaped barrier wall and passagewayaa lJ-shaped barrier wall extending about three sides of one of said passageways, two transverse barrier walls d1 sposed on opposite sides of the other of said passageways with their outer edges disposed clear or the ELI-shaped barrier wall and their rear edges united by radial flanges.

3. An insulator unit having a central or body portion provided with two interlinked,

passageways, a lJ-sha ed barrier wall extending about three'si es of one of said passageways, two transverse barrier -walls disposed on opposite sides of the other of said passageways, and two semic1rcular flanges extendin radially outward from the ends of said -shaped wall and joined to the rear ends of the two transverse walls.

In witness whereof, I have hereunto set my hand this 13th day of September, 1921.

EDWARD M. HEWLETT. 

